The present disclosure involves a novel bracket assembly for mounting cylindrical devices for use with plumbing systems, to a building surface, while allowing easy installation and removal of the cylindrical devices as desired. Although other uses are contemplated, for illustrative purposes the bracket is used to secure a thermal expansion tank such as is commonly used in both potable and non-potable hot water plumbing systems. Illustrations for this application are included at the end of this text.
In a hot water heating system as is commonly found in domestic potable water supply or non-potable hot water space heating systems, the fluid contents are subject to expansion and contraction as the water is heated and cooled. As heated water is withdrawn from the hot water heater cold water is introduced into the tank. If five gallons of cold water are added then when that water is heated to 100° F.-200° F. by the heater, the water expands. If the water is added during winter to a heater located in areas where snow is on the ground, the inlet water temperature can be slightly above freezing, namely 32° F. or 0° C. Because water is not compressible under normal conditions, the surplus or deficit in volume can cause a pressure changes and displacements within the piping system.
Most particularly, when the water is heated and there is no flow because all valves, faucets, backflow devices, check valves, etc., are in a closed state, the system pressure can increase dramatically. This can place a significant and potentially dangerous strain on system components, including valves, piping, and elements of the water heating equipment. Further, because most such systems are isolated for public safety reasons from the common water source (e.g., the city water main in potable hot water systems) by a one-way “anti-backflow” valve, the pressure increase cannot be relieved by a back-flow out of the local system, and the system is sealed, or closed. Water heating equipment may be furnished with pressure-relief devices to address this situation, but such devices are notoriously subject to failure due to corrosion or buildup of mineral deposits from the domestic water supply, especially over the multi-year life of a water heater.
An auxiliary device introduced into the water heating system to ameliorate this situation is the thermal expansion tank. This expansion tank typically includes a small hollow container incorporating a flexible diaphragm which divides the interior of the expansion tank into two compartments. One compartment has an opening which is connected to the water piping so that water may enter and the other compartment has an air valve so that an air pressure charge may be injected into the tank.
When this expansion tank is connected to the water system piping on the incoming side of the system, upstream of the water heater, and when a charge of air is injected at an appropriate pressure into the expansion tank compartment, the dual chambers of the expansion tank act as a buffer for pressure changes in the system and relieve the stresses on the closed system caused by pressure changes arising from expansion of heated water. When the water is heated and the pressure rises then water flows into the expansion tank and relieves the over-pressure condition. When the water cools or the system flows (e.g., by opening a faucet), water returns from the expansion tank to the piping. This equipment and technique have been incorporated as a requirement into many building codes and construction specifications.
When the weight of the maximum incursion of water into the expansion tank chamber is taken into account, the entire unit for a typical residential hot water installation may weigh as much as 18-35 pounds, depending on the system capacity and the level of incoming water pressure. However, with the exception of generic requirements in some commercial and government documents, the specific method and apparatus used to secure the expansion tank against vibration and movement relative to the building structure is largely left up to the installer, and is typically an afterthought to the building construction. Currently available brackets are cumbersome to install and use, and require large brackets because the brackets provide a bottom shelf on which the expansion tank rests.
There is thus a need for a simpler and lighter method and apparatus to hold the expansion tanks.